Confuse for the Sealion's Political Rules

[Quidam]

In the Europe Only Version (Not Global rules),the rules said US and Soviet will declare War to Axis on its following turn.

If Germany capture London in Round 3, is Soviet declare war is Round 3 on its turn? Or Round 4 on its turn?

[Alsch91]

Round 3.

[Quidam]

the other question about some tactics.

I found one rules said that the tranport can’t offload land unit to enemy territory by using amphibious assult when the enemy submarine in that sea zone that the transport without warship.

If i use submarine with the transport, can i do the amphibious assult in same situtation?

[Witt]

Yes you could Quidam. It is a warship.